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(N0 M de1 I f U 1- 2Sheets-Sheef1. '0. A. LE BOURG 8: V. MLOOSSEQ METHODMOLDING WITH MOLTEN WAX FOR REPRODUCTION OF CASTS.

4 No. 537,297. I Patented Apr.. 9,1895.

UMTED STATES PAT NT @nricn.

CHARLES A. LEBOURG AND VICTOR M. OOSSE, OF NANTES, FRANCE.

METHOD OF MOLDING WITH MOLTEN WAX FOR REPRODUCTION .OF CASTS.

SPECIFICATION forming part of Letters Patent No. 537,297, dated April 9,1895.

Application filed February 23, 1894. Serial No. 501 ,801- (No model.)

- homogeneous cores capable of resisting heat in casting, and to avoidthe necessity attending existing processes of retouching the castsproduced.

Hitherto the methods in use of applying molten wax to the formation ofpatterns employed in the reproduction of metal casts have been attendedwith imperfections and uncertainty of results, besides extravagance incostwhich has rendered them practically unprofitable. For instance themethod in which the wax pattern is cut into sections and afterwardpieced together on the core, destroys sharpness of form, besidesinvolving considerable expenditure of time and labor,

and being uncertain of success. Again, the present method of forming thecore by pressing moist clay into a hollow wax pattern has the objectionthat evaporation during the drying of the clay core within the patterninjures this interior pattern, and detaches fragments therefrom. Anotherexisting method, according to which a metal core is cast embedded in aplaster core, has the defect that gas liberated from the substance ofthe core by heat interrupts the flow of metal around the core,- and socauses irregularities in the cast.

According to our invention we effectually obviate the defects'andobjections above described by improvements more particularly relatingtothe preparation of the patterns, the formation of the core, and thecasting of the wax,'the other parts of the operation remaining as inexisting processes, and we attain our objects in the manner hereinafterdescribed, reference being had to the accompanying drawings, in which-Figure 1 represents a perspective elevation of a proof taken from aplasterreproduction tern.

of the original-object, Fig. 2 being a second proof of the same, reducedby scraping or grinding its surface. Fig. 3 shows the plaster core box,the upper part being formed in sections and tapered while its lower partmay be made'in one piece or in sections and tapered. Figs. 4 and 5represent in section an elevation and plan respectively of the gelatinemold and core, prepared for the metal cast as hereinafter described.Similar letters refer to similar parts throughout the several views, a abeing sections forming the upper part of the core box to form the cores;1), metallic rod and core iron; 0,

gelatine mold'; d, wax pattern representing thickness of metal to becast.

In carrying out our invention we first reproduce the original object inplaster in any ordinary manner. Two proofs are taken from it. One ofthese proofs is retouched by the artist and forms a permanent artisticpat- See Fig. 1. The other or reduced proof, shown in Fig. 2, has itsentire surface scraped 7 5 .to a depth equal to the thickness of themetal cast required, and constitutes the pattern for producing the core.Both proofs are provided with similar dowels and joining pieces arrangedin exactly the same manner.

The pattern shown inFig. 1 is used for the production of a hollowgelatine mold, or a hollow plaster mold formed in sections, withasuitable shell or casing provided with dowels. The reduced proof?shown'in-Fig. 2, is used to form a core box in sections, upon the casingof which are shown the dowels.

The plaster core-box Fig. 3 has its upper part formed in transversesections a, of nar row dimension, each section being numbered. 0Prepared clay is rammed into the'core box thus constructed by removingtheupper part of the core box shell and sections, a suitable metallicrod b, with core iron and cross-piece, being placed upon the uncoveredlower part so that the clay of the core will be supported by the coreiron, which serves also to form the necessary dowels. The first sectionof the upper part of the core box being then put in place, pressure withthe fingers is appliedjroo upon the clay within the cavity of the corebox. The'sections a. are finally inclosed in their shell and theformation of the core is completed when it has dried and set to thenecessary consistency, it being then a seamless homogeneous piece ofclay having a metallic rod or core firmly embedded in its substance. Inthe composition of this clay it is essential that there should be nocalcareous constituent. \Vith the same core box as many cores as arerequired may be formed each reproducing accurately the reduced proof ofthe model. The core thus constructed is placed inthe hollow mold ofgelatine or in the plaster sections formed from the proof pattern ormodel, Fig. 1, by fixing its dowels or joining pieces in the lower halfof the shell containing half the gelatine mold 0. See Fig. 4. Thegelatine is withdrawn from the upper shell and placed upon the uncoveredpart of the core. Thus the core is entirely surrounded by gelatine asshown in Fig. 5, a space (1 being left between it and the gelatine equalto the thickness of plaster scraped from the second proof to form thereduced proof, Fig. 2. Into this space d the wax is cast. By this methodof inclosing the molded core with wax, handling is dispensed with, and asuccessful cast is insured reproducing the model in its entirety andsharpness of form, and requiring no retouching by the artist. The singleseam left by the mold may be readily removed by any ordinary workman.Several reproductions of the proof pattern may be obtained with the samegelatine mold.

To complete the permanent mold we cover the wax proof on the core formedas above described with putty or prepared clay, and with a shell ofsufficient rigidity. The mold so prepared is removed to a stove to meltand remove the wax. It is afterward placed in a kiln to get rid of theorganic matter, and finally the bronze is cast which takes the exactplace of the wax and forms afaithful copy or reproduction of the proofmodel, Fig. 1.

The core constructed according to our invention has the advantages ofcapacity to effectually resist heat and molten metal, beingnon-calcareous. It is one seamless homogeneous piece firmly secured onthe metallic core red I) embedded within it, and it gives out no vapor.

We claim as our invention- 1. The herein described process of producinghollow castings consisting in making from the original work or object tobe reproduced, two proofs in plaster, one to be retouched by the artist,and producing from the one retouched the hollow mold, reducing theother, as by scraping over its entire surface, producing from this acore box, making cores from this latter, fitting the cores in the hollowmold and making hollow-castings from the two, substantially asdescribed.

2. A core-box having its upper part formed of transverse sections a ofnarrow dimension, in combination with a metallic rod 12, for the purposeof forming by means of ramming or pressing, a seamless homogeneous coresupported in the manner shown, and as described.

In testimony whereof we have signed our names to this specification inthe presence of two subscribing witnesses.

C. A. LE BOURG. v. M. cossn. Witnesses:

D. BoRHUI, G. RoUoUI LAGUIRE.

